1. Field of the Invention
The present invention relates to telecommunications systems and, particularly, to an improved H.323 system.
2. Description of the Related Art
The International Telecommunications Union (ITU) Recommendation H.323 describes a set of devices and protocols for multimedia communication over packet-switched networks. The four main components defined by the specification are clients (also referred to as terminals), multipoint control units (MCU), gateways, and gatekeepers. Clients and gateways are generally referred to as endoints. The H.323 components are organized into administrative domains called “zones.” Typically, each zone is managed by a gatekeeper.
Direct extension dialing for internal calls may be provided within each zone, i.e., by the gatekeeper. Thus, for example, users within a single company may need only to dial two or three digits to call other users within the company. However, it is frequently the case that users from more than one company may be served in a particular zone. In this case, each company would like to communicate within the company as if that company owned their network, and each company would like to take advantage of direct extension dialing, i.e., a “virtual private network.” Unfortunately, under present H.323 systems, a gatekeeper can support only one numbering plan for a single zone. Consequently, there is no way for the individual companies to manage an individual extension-based dialing plan when a common gatekeeper is used to manage the single zone serving users from multiple companies; instead, internal calls must be placed using the full phone number. One alternative is to use a separate gatekeeper for each company, but this multiple gatekeeper alternative adds hardware and maintenance costs.